'The Soft Science of Dietary Fat' (i.e. pass the bacon)

Great Debates
1

I just read an investigation from The National Association of Science Writers called “The Soft Science of Dietary Fat”. It’s seventeen pages, but in a nutshell it says that despite what the health gurus say, there’s no proof that limiting your fat intake will extend your life.

Some points from the report:

Despite a shift away from fats, Americans have gotten fatter, and heart disease has increased dramatically. (You probably already knew this one)

There is only a subtle correlation between diet and cholesterol level (and only a subtle correlation between cholesterol level and heart disease.)

It is debatable whether eating a high level of saturated fats will lead to an early demise.

Japanese doctors routinely advise patients to increase cholesterol to prevent stroke. American scientists have verified the low cholesterol/stroke link, and found a host of other problems associated with low cholesterol, including an early death.

People who cut their fat intake often switch to high carbs, which can be worse than the fat.

The low fat diet has proven to be a failure for the purpose of weight loss.

It also provides a history of how the US government’s recommendation for fat intake came to be.

What do you think of the report? Is The National Association of Science Writers owned and operated by the American Lard Foundation?

I checked out the diet recommendations on various legitimate medical sites, and they all still preach the “limit your fat (especially saturated fat) intake” mantra. So, what I really want to know is, if this is in fact an accurate an unbiased report, why is the information not more widely reported?

2

I don’ worry me 'ead 'bout it much none. I may not get out as much as me Grampys done, but Oi walk a fair few milers alle day!

I suspect its a matter of excercise, personally.

3

Your suspicion is right. And wrong. It’s a little bit more complicated than that.

I am speaking from my own experience, as a person who once upon a time weighed 180 pounds and was buff, then ballooned to 280 pounds, and now is having incredible difficulty getting his weight to stabilize.

The body absolutely craves complex carbohydrates. The calorie/carbohydrate ratio is 4 calories to 1 gram of carbs. It’s a very efficient fuel, but since people tend to binge on them without even realizing it, for the most part it’s wasted.

Fats come in at 9 calories per gram. Fats are even better than carbohydrates for fuel. Ever hear of your “second wind”? That’s fat kicking in.

Proteins are 4 calories per gram. They’re excellent muscle builders.

With that, here’s how you get fat. You cut your fat dramatically, you double your carbs, and you don’t pay any attention to proteins. Then you don’t exercise. Thus, you have totally negated any benefit you had from your fat reduction.

Another lovely little tidbit: 3,600 calories equals one pound of fat. The average American diet is far more than that per day, I would guess. After factoring in resting consumption, it’s not unreasonable to guess that weight can be gained (real weight, not just right-after-dinner weight) at the rate of about a half-pound per day. It sneaks up on you. I know it snuck up on me.

And exercise doesn’t always do it either. I just ran a 6:15 mile tonight and I am 20 pounds overweight according to the Air Force regs. There are two requirements to losing weight:

1)Eat less. I mean it. It’s hard as hell to do, and sometimes it genuinely hurts, but you have to do it. What you eat, in my experience, is generally irrelevant, unless you really want to go down fast. Salads are great for that, incidentally, that’s what I do when I need to crash diet, but I would recommend against it. Just eat less.

2)Run your friggin’ tukkas off. If you can’t do that, walk. Or at least take your hand out of that bag of Fritos and don’t hurt yourself worse. Get some exercise. Running at my pace consumes 1,000 calories per hour, and that elevated rate continues for hours after you’re done.

The point of this dissertation is that the Atkins Diet (all fat, no carbs), the low fat diet, and all diets in between don’t make a damn bit of difference unless you go out and do something. And sometimes, as in my case, the weight just doesn’t come off but your build changes and your strength improves. So don’t necessarily expect big, noticable weight loss no matter what you do. If it happens, it happens. Exercise is never a bad thing, though.

[sub]I wasted my 1,000th post for this?!?![/sub]:slight_smile:

4

This ain’t news to a whole bunch of us.

5

As others have said, it’s not your diet alone that makes you unhealthy, it’s sitting on your (fat?) ass all day long. Exercise is the key to overall health, not just keeping your body fat levels low.

Also, the type of fat that you’re eating seems to matter quite a bit. Trans-saturated fats are thought to be the worst, and polyunsaturated the best (although I’m not 100% certain of that last bit).

There’s a study I always like to toss around comparing the effects of two different exercise regimes. One is all cardio, the other is half cardio and half weight-lifting. The results are pretty astounding.

6

ultrfilter, it’s mono-unsaturated that are the best and trans-unsaturated the worst.

poly-unsaturated lower LDL and HDL
saturated raise LDL and HDL
trans-saturated raise LDL and lower HDL
mono-unsaturated raise HDL and lower LDL

confused yet?

basically cut down the proportion of peanuts, meat and dairy (saturated), margarine and synthetic fats (trans) and increase proportions of soya and sunflower oils (poly) and olive or canola oils (mono).

still, the average man should have a TOTAL fat intake of NO MORE than 80 g per day and a TOTAL calorie intake of NO MORE THAN 2500 kcal a day.

7

Make the majority (like 80%) of your diet fruit and vegetables. Eat enough lean meat (salmon/turkey etc) to get adequate protein and to make you feel full.

Works for me. If you get hungry eat an apple,or a grapefruit, or some brocolli and carrots instead of chips. I also eat very little bread. Fruit and vegetables handle the fiber situation. Also sip on green tea between meals, it helps curb your appetite a little. Drink water only, unless you are drinking for a buzz.

8

Last I heard though, trans fats don’t raise your LDL cholesterol levels as much as saturated fats do.

trans fats are the food villain du jour. 25 years ago, sugar was the absolute worst thing in the world you could possibly eat. Then, 20 years ago, salt took the blame for every ill of society and everybody forgot about sugar. Then, about a decade or so ago, saturated fat became so vilified that McDonalds reacted to public outcry by replacing the lard in their French fry cookers with partially hydrogenated vegetable oils. Now, today, it’s trans fats that are The Enemy [TM], and so McDonalds is now vilified for their decision to switch to partially hydrogenated vegetable oils in the first place.

There is, currently, pretty good evidence that trans fats are about as bad for you as saturated fats are. There’s almost no evidence that trans fats are any worse for you than saturated fats are, though.

I’d hardly put peanuts in the same category as meat and dairy products. One ounce of peanuts contains 14 total grams of fat but only 2 grams of that fat is saturated. That’s the same proportion of total-to-saturated fat that’s in olive oil!

9

That can’t be right.

At 9 calories per gram, 28 grams to the ounce, and 16 ounces to the pound, one pound of fat should be 9 * 28 * 16 = 4032 calories.

Unless you’re talking about Troy pounds. :wink:

10

That assumes that fat is perfectly metabolised. It may well not be. 3600 calories gives you roughly a 90% efficient metabolism, which is pretty good.

Remember that caloric counts are measured by burning things, and that the human digestive process is not as fuel-efficient as combustion.

11

Ah, but Airman Doors said that consuming 3600 excess Calories produces 1 pound of body fat. (Or at least, that’s what it sounded to me like he said.)

If burning 1 pound of fat produces 4032 Calories of heat energy, how can 1 pound of fat be created by only consuming 3600 excess Calories of food? That would mean that human metabolism was 112% efficient.

12

Common wisdom is that you have to consume/burn roughly 3600 extra calories to gain/lose a pound of fat.

**

I wasn’t clear. Caloric content of food items is determined by setting them on fire and measuring the temperature change of the environs. That’s not a total mass-energy conversion, and the human metabolism is nowhere near that efficient.

I agree that, given that, it does seem a little odd that the same number is required for losing and gaining. MHO is that there’s a lot of simplifying going on by the time that we hear about any of this.

13

Hrm …

Maybe this Common Wisdom is only half accurate; i.e., the “burn … lose” portion is accurate, but the “consume … gain” portion isn’t. Or something.

14

All the information regarding HDL and LDL seems inconsequential, given this line from the report:

“The effect of diet on cholesterol levels is subtle for most individuals–especially those living in the real world rather than the metabolic wards of nutrition researchers–and the effect of cholesterol levels on heart disease is also subtle.”

Further, the U.S. Surgeon General’s Office funded study mentioned in the article concluded that cutting down on saturated fats will only increase your life expectancy by only three to four months.

My question is, why worry about fat at all, given the information in the NASW report?

15

Cecil agrees:

http://www.straightdope.com/classics/a2_313.html

Only thing I can’t figure is that, in the above link, Cecil says:

“When your metabolism is in “rest” mode, you burn mostly glucose [ … ] But when you engage in sustained, strenuous (i.e., aerobic) exercise, your system shifts gears and you start metabolizing body fat.”

We switch straight from metabolizing glucose directly, to metabolizing fat? What happened to glycogen?

16

I don’t think you’re ever getting more than 50% of your energy from burning fat, so there’s always some glucose usage. IIRC, glycogen is primarily used anaerobically (i.e., without oxygen), so during aerobic exercise, you’re not going to use much glycogen. I could be wrong, though–I’ll have to check.

17

From the O.P.:

Um … with respect to the clause I’ve underlined, the report says the exact opposite of this.

From Part 9 of the report, titled The Epidemic That Wasn’t:

“To Rosenberg and others at NCHS, the most likely explanation for the postwar upsurge in coronary heart disease deaths is that physicians slowly caught on to the new terminology and changed the wording on death certificates. ‘There is absolutely no evidence that there was an epidemic,’ says Rosenberg.”

18

Ironically, you eat a lot less on the high protein diet. At least, that’s my experience. When I was on it, and limited my carbs to under 20 a day (and that’s freakin’ HARD to do) I ate a lot less. And I wasn’t as hungry. The high protein stuff seemed to fill me up faster and stay with me longer. High Carb meals, OTOH, seem to spark my hunger. My cholesterol went up the first month, but came back to normal pretty quickly.

19

I may be misremembering entirely, but isn’t glycogen the form glucose takes when stored in muscles for energy?

20

I think this effect comes from insulin spiking. You eat an ungodly amount of carbs (and an average meal for an average american includes an ungold amount of carbs), and your pancreas floods your body with insulin to nutralize the huge blood sugar spike. Well, the huge spike eventually causes your blood sugar to drop rapidly, leading your body to believe you’re in need of food. Hence, you get ‘false hunger’ pains, sort of a complex version of sugar cravings - which then causes you to binge on carbs again, and the whole thing repeats. That’s part of the reason why ungodly high carb diets will make you balloon up - your body will give you false signals that you’re hungry when you’re really not.

I might be totally off, but this is a rough explanation from memory from a few sources, and personal experience. When I low-carbed, my body seemed MUCH more in tune with when I was actually hungry - and the real hunger feeling was different from the false hunger feeling. Also, very much less frequent.